1. Field of the Invention
The present invention relates to a process for making biomass pellets, and more particularly to a process that is scalable for mass production using a variety of biomass feedstock sources.
2. Description of Related Art
Renewable energy sources can reduce dependence on fossil fuels, reduce greenhouse gas emissions, and create economic opportunities. Biomass is a plentiful renewable energy source and considerable research and development has been done on ways to economically convert raw biomass into a fuel source that can be used in place of traditional fossil fuels. Liquid biofuels, such as ethanol and biodiesel, are growing in use as transportation fuels. Wood is a renewable energy source that has be used as a heating fuel for thousands of years. More recently, wood waste products have been used to form wood pellets that can be used as a heating fuel. Wood pellets are extremely dense, can burn every efficiently and have a compact size and regular geometry. These characteristics contribute to ease in packaging, reasonable transportation costs, and ease in handling by automated feeding systems. However, wood takes a number of years to replenish and availability and cost of the waste wood supply is dependent on the underlying lumber and paper-making industries that produce the waste product.
Crop waste products, particularly corn, also have been used to form biomass fuel pellets. However, pellets formed from corn do not produce as much energy as wood pellets, and the availability and cost of the feedstock is dependent upon the underlying industry.
Other research efforts have focused on using switchgrass, an energy crop, to form biomass pellets. However, switchgrass lacks natural binding properties. As a result, even on small scale production lines, it is difficult to product switchgrass pellets with high density and durability.